In order to further understand the contents, features and effects of the present invention, the following embodiments are described in detail.
Referring to fig. 1, the construction process of the pile wharf of the present invention includes the following steps:
s1, carrying out preparation work before construction;
this step includes, but is not limited to, the measurement and evaluation of engineering characteristics and quantities and engineering hydrogeological conditions, and may also include the measurement and evaluation of tidal conditions.
In the preparation work before the construction, measure the position of pile foundation pier and design pile foundation pier's plane overall arrangement, including pile foundation pier's length, width, the position of arranging bulk cargo berth, multipurpose berth, workboat berth along the bank, pile foundation pier's structural style (if adopt high pile beam-slab formula and high pile pier combination's pattern etc.), the position and the line number of pile foundation, column number, the framed bent interval of pile foundation.
The hydrogeological environment mainly reflects the hydrogeological and geological conditions of a construction site, the burial depth of the static water level in the region of the construction site and the burial depth of the static water level in other regions. The properties of surface groundwater (for example, belonging to the type of stagnant water in the upper layer), and the properties of surface groundwater (for example, mainly supplied by atmospheric precipitation and drained in the form of evaporation, and the water level varies with seasons). Whether the underground water of the construction site has strong corrosivity on the concrete structure or not, and the corrosive influence of the underground water of the construction site on the steel bars in the reinforced concrete structure under the condition of alternation of dry and wet conditions and the like.
S2, performing precipitation operation in the construction site;
in the step, a drainage ditch is arranged on the operation site, a precipitation well is arranged, drainage and precipitation treatment is carried out on surface water and underground water, the water level of the underground water in the soil body is reduced, and the strength of the supporting structure of the operation site is improved.
According to the actual conditions of the pile foundation wharf area, a drainage ditch can be dug for surface layer water drainage operation one month before working, a plurality of dewatering wells are dug at corresponding positions according to process requirements, the underground water level is reduced, and the loads of a drilling machine, a crane and the like can be met after the surface plain filling and the silty clay are consolidated into blocks. A drainage ditch is dug along the front line of the vertical pile foundation wharf and is directly communicated to a river mouth, accumulated water in the drainage ditch is discharged to the river mouth by using a water suction pump, the distance between every two adjacent drainage ditches is 50-70 m, the depth of each ditch is 1.5m, and the width of each ditch is 2 m.
S3, constructing a mountain stone sidewalk in a construction site for operators and working vehicles to pass through;
according to the design of a pile position layout diagram of a pile foundation wharf, two mountain skin stone access roads are built in a wide range in the north-south direction of the pile foundation wharf, the access road width is 7.5-10 m, a carriage return island is filled in a position where a vehicle needs to be staggered, a 10m wide connecting access road is built in the east-west direction, the distance between every two adjacent east-west connecting access roads is about 140m, and the method is used for steering, turning and transporting reinforcement cages of concrete tank trucks; and constructing a long stone access road in the south-north direction of the sea side of the pile foundation wharf, wherein the width of the access road is 10m, and the access road is connected with a connecting change road. The thickness of the three mountain skin stone pavements is about 1m, and the three mountain skin stone pavements and a constructed pavement behind the pile foundation wharf form a closed circulation loop, so that the three mountain skin stone pavements are beneficial to dispatching of mechanical equipment and material transportation.
S4, performing cast-in-place pile construction to form a pile foundation;
in this step, the construction process of the pile foundation includes the following steps: 1) measuring and paying off the pile position; 2) embedding a steel pile casing at the pile position; 3) moving the drilling machine equipment to be in place and drilling a hole; 4) detecting the depth and the verticality of the hole and cleaning the hole; 5) installing a prefabricated reinforcement cage into the pile hole; 6) installing an underwater concrete guide pipe; 7) underwater concrete pouring; 8) the rig apparatus is displaced. The drilling equipment is selected to be reverse circulation type drilling equipment, namely, slurry is injected into the pile hole and is sucked out through the slurry hole at the bottom of the drill bit. In particular, the amount of the solvent to be used,
firstly, preparation work before the construction of the cast-in-place pile is carried out, main construction managers and technicians carefully learn, familiarize and examine design drawings, fully know design intentions and technical requirements, thoroughly investigate the field situation and carry out technical background in advance; the raw materials of the concrete, such as cement, broken stone, medium coarse sand, an additive and the like, and the steel bar are determined to be qualified, the concrete is reported by a qualified laboratory in a mixing ratio, and the qualified concrete can be used for construction; the organization and arrangement of personnel are in place, the technical management of the construction site and the personnel of the construction team have been trained before the post correspondingly, and the coordination work of the construction is well done. The construction machinery equipment is equipped in place and overhauled and debugged, and the start-up requirement is met. The construction access road can meet the normal traffic of various mechanical equipment, and personnel and the mechanical equipment can directly enter the field for operation. And (4) clearing obstacles in the construction area of the cast-in-place pile, leveling the field, filling a working platform and arranging a drainage system.
And then carrying out measurement and paying-off operation, before the machine enters a field, carrying out pile position lofting and retesting by using a total station by tissue survey personnel according to the closed conducting wire points, paying out a pile position line, additionally arranging a pile position control pile and reinforcing, and selecting the position of the control pile in a place which is not easy to move and can not be pressed by a vehicle. And reports the supervision engineer for recheck.
The excavating of the mud pit is provided with a mud pit which is used for being matched with drilling equipment, and the mud in the cast-in-place pile construction process has the following effects: the drilling mud consists of water, bentonite and additives. In drilling, because the relative density of the mud is greater than that of water, the same high water head is arranged in the casing, the hydrostatic pressure of the mud is greater than that of water, a layer of mud skin is formed on the wall of the borehole, seepage inside and outside the borehole is blocked, and the borehole wall is protected from collapse. In the embodiment, the reverse circulation type drilling equipment is adopted, and slurry in the equipment is continuously pumped out from the center of the drill rod through the bottom of the pile hole by a slurry pump, so that the slurry generates continuous descending flow velocity outside the drill rod in the hole, and particles such as sand and stone generated by drilling are taken out. The preparation method of the slurry comprises the following steps: before pulping, the clay blocks and bentonite are smashed as much as possible, so that the slurry is easy to form during stirring, the stirring time is shortened, and the slurry quality is improved. The size of the mud pit is proper to avoid mud flowing out, and a sign board is hung (for example, the mud pit is dangerous and does not need to be close).
And then, carrying out steel casing embedding operation, after lofting of the measuring group, guiding two control piles at each side in the longitudinal direction and the transverse direction, wherein the distance between the two control piles is 2m, and the control piles are used for controlling the axis deviation during drilling. After the pile is guided, the cross wire is pulled, and a drill bit of the drilling machine is adjusted to the center of the cross wire by a wire hammer. According to the requirements of design drawings, a steel pile casing is dug and embedded, the wall thickness of the steel pile casing is 8mm, and the embedding depth of the steel pile casing is 7.7m (from the original mud surface plus 5.7m to minus 2.0 m). The problems of necking, collapse and the like caused by poor geology of the muddy clay can be reduced by using the steel casing, the concrete pouring quality can be effectively guaranteed by using the steel casing, the water level change area is penetrated, and the long-term durability of the pile foundation can be guaranteed.
After the steel casing of the earth excavation face is buried, a cross line is drawn from the control pile, a plumb bob is matched with drilling machine equipment to adjust the deviation and the inclination of the casing, and the allowable deviation of the casing is required to be 5.0cm according to the specification. And (3) burying a back-drawing cross wire in the steel casing to guide a control point on the steel casing, and manually ramming the periphery of the steel casing by using cohesive soil in a layering manner.
The selection and the embedding of the steel casing follow the following key points: the inner diameter of the cylinder is 200mm larger than the designed pile diameter; when embedding, the vertical line of the center of the steel casing is coincided with the center line of the pile foundation; the embedding depth of the steel casing is determined according to design requirements or the hydrogeological condition of a pile position; the joint of the steel casing requires no projection in the casing, and has the advantages of tensile resistance, pressure resistance and no water leakage.
And then, carrying out bored pile hole forming construction, after the drilling machine equipment is in place, retesting and correcting, aligning the drill bit to the center of the drill hole, and enabling the base of the drilling machine to be horizontal. The low-gear slow drilling is carried out during the drilling so as to ensure the accuracy of the pile position, the drilling is carried out at a low speed and thick slurry in a sand layer, the drilling and pore-forming speed is controlled by adjusting parameters such as drilling pressure, rotating speed, slurry index and the like, and the phenomena of hole inclination, hole shrinkage, hole collapse and the like are prevented. Specifically, the method comprises the following steps: slowly drilling when drilling, accelerating drilling after the drill bit completely enters the stratum, and making a drilling record; in the drilling process, the pile position is controlled by adopting a longitudinal and transverse cross line, and the pile position and the verticality are corrected every shift and measurement group of a drilling machine every other day, so that the pile position and the verticality of the pile meet the requirements of specification and inspection; and (4) after the drilling is finished, checking the hole by using a hole checking device, wherein the height of the hole checking device is 6m, and the diameter of the hole checking device is 5-10 cm smaller than the designed pile diameter.
Then carry out pore-forming inspection and detection, the inspection of pore-forming quality is the straightness inspection that hangs down at first, pay attention to three aspects during the pore-forming: firstly, before drilling, whether the center of a drill bit and the center of a pile position are on the same plumb line or not must be checked, the adjustment is checked along with the direction, secondly, along with the drilling of a drilling machine, whether the hole position deviates or not is often checked (measurement lofting and check), thirdly, the operation regulation is strictly followed, the drilling machine is prevented from shaking, and the drilling stability is kept. And secondly, checking the hole depth, designing the pile top elevation and the pile casing top elevation according to a drawing, calculating the depth of the pile hole (the depth of the pile hole is the pile casing top elevation-the designed pile bottom elevation), measuring the hole depth by using a measuring rope when the drilling is close to the depth of the pile hole, and then slowing down the drilling speed until the depth of the pile hole. When the designed hole depth is reached, the drilling is stopped, and then a supervision engineer is reported for inspection. And thirdly, measuring the sediment, and checking the hole depth by adopting a heavy hammer method after the pile depth meets the design requirement and is qualified by a supervision engineer. After the hole inspection device is used for inspecting the hole diameter to meet the design requirement, a supervision engineer is required to inspect the hole position, the hole diameter and the verticality (the hole inspection device of the steel reinforcement cage is adopted for inspection).
The method for checking the aperture and the verticality of the pile hole comprises the following steps: after the first hole cleaning is finished, a hole inspection device (a steel reinforcement cage with the diameter being 8-10 cm smaller than the design diameter of the pile and the height being 4 times of the hole diameter) is used for inspecting the hole, the hole forming hole diameter is not smaller than the design diameter, the inclination of the hole can be visually seen in four directions through an ultrasonic detector, and a supervision engineer is requested to perform recheck after the requirement is met.
And (5) cleaning the holes after the holes are inspected to be qualified. When cleaning the hole, the water level in the hole is kept 50cm higher than the bottom of the protective cylinder. The specific gravity of the slurry after hole cleaning is controlled to be 1.03-1.1 g/cm3About, the sand content of the slurry should be less than 2%, and the viscosity should be controlled within 17-20 Pa.S. And cleaning the holes immediately after the hole forming inspection is qualified. And keeping the normal circulation of the slurry, and replacing the slurry with higher density and the drilling slag until the slurry index in the hole reaches the design requirement. Before the steel reinforcement cage and the guide pipe are arranged, the slurry hydrometer is adopted again to check the slurry index and the thickness of the sediment layer, and a supervision engineer can check the slurry index and the thickness of the sediment layer to be qualified to carry out the next procedure. The specific gravity of the slurry after hole cleaning is controlled to be 1.03-1.1 g/cm3The sand content of the slurry is less than 2%, and the viscosity is controlled to be 17-20 Pa.S.
And then installing a reinforcement cage in the pile hole, wherein an ultrasonic instrument must be firstly put into the pile hole to probe the pile hole before the reinforcement cage is hoisted, and image data is recorded. The main reinforcing steel bar connecting mode adopts single-side or double-side welding, steel bar cage section processing, section hoisting and section lapping, and all mechanical indexes of the connecting reinforcing steel bar can be formally used after on-site witnessing by a supervision engineer and qualified laboratory spot inspection. All indexes of the steel bar processing must meet the specification requirements.
The steel reinforcement cage is hoisted by a crawler crane, and after being hoisted by the crane, the steel reinforcement cage is placed into a qualified pile hole. After the concrete is poured into the hole, the steel reinforcement cage is firmly positioned, and the steel reinforcement cage is prevented from falling or floating upwards in the process of pouring underwater concrete. The positioning and elevation after the steel bar cage enters the hole must be accurate.
The reinforcement cage is divided into two types, wherein the first type is a 1000mm reinforcement cage, the length is 64.67m, the reinforcement cage is divided into three sections (two sections are 24m long, one section is 16.67m long), and the longest 24m weight of a single section is about 3.3 t; the second type is an 800mm steel reinforcement cage with the length of 47.82m, which is divided into two sections (one section is 24m long and the other section is 23.82m long), and the longest 24m weight of a single section is about 1.6 t. And considering the longest length of a single section of the reinforcement cage of 1000mm according to 24m during hoisting checking, and the others meet the hoisting requirements.
Before hoisting operation on a construction site, relevant personnel at an organization project part check and accept a hoisting machine tool and a material entering the site, and after the materials are qualified, a crane driver performs a load test and an empty hook test on a crane; and (5) carrying out inspection work before hoisting on components such as a steel reinforcement cage and the like, and hoisting and parking to a specified hoisting position after the components are qualified. The method is characterized in that a 25t automobile type crane is selected according to the specific situation of a site and the comprehensive consideration of mechanical use, the maximum rated lifting capacity is 25t, the maximum working amplitude is 32m, and the minimum working amplitude is 10.2 m.
Then, an underwater concrete guide pipe and a storage hopper are installed, the inner diameter of the guide pipe is 300mm, the inner wall of the guide pipe is required to be smooth and straight, no local convex and concave exist, the inner diameters of all sections of guide pipes are consistent, and the connection is stable. Before the conduit is installed and used, experiments such as watertight test, joint tensile strength and the like are carried out, and the conduit is put into use after being qualified. Before the catheter is placed, each section of catheter is numbered, the length is noted, and the joints are connected tightly and do not leak water.
The storage hopper volume is determined according to calculation, the buried depth of the guide pipe is ensured to be not less than 1m after the concrete is poured in the first disc, and then the bottom of the guide pipe is ensured to be buried 2m below the top surface of the underwater concrete in the construction process, so that the phenomenon that muddy water in a hole is flushed into the concrete to cause the discontinuous concrete pouring surface and pile breakage is avoided.
And then, carrying out secondary hole cleaning operation, and after placing the reinforcement cage and the concrete guide pipe, detecting the specific gravity, viscosity and sand content of the slurry. If the underwater concrete is not qualified, secondary hole cleaning is carried out through conduit mud jacking, and the underwater concrete can enter an underwater concrete pouring procedure after the underwater concrete is qualified.
Then underwater concrete pouring is carried out, and the underwater concrete pouring is an important process for the construction of the bored pile and special attention should be paid. And after the hole forming quality is qualified, the drilling can be started to perform the pouring work. The thickness of the sediment layer at the bottom of the well should be measured again before perfusion. If the sediment thickness exceeds the design and specification requirements, the sediment can be suspended by spraying the sediment to the bottom of the hole for 3-5 min by using a spraying method. After the concrete tank truck arrives at the site and before concrete is poured, slump inspection must be carried out, and measures such as adding additives, adjusting workability and the like are taken for the concrete retreat which does not meet the slump requirement. After the first batch of concrete is poured into the bottom of the hole, the height of the top surface of the concrete in the hole is immediately detected, and the embedding depth of the guide pipe in the concrete is calculated, so that the concrete can be normally poured if the embedding depth meets the requirement. After the start of the perfusion, it must be carried out continuously, with a strict mid-stop. Concrete mix is prevented from overflowing the top of the hopper or falling out of the hopper into the bottom of the hole during the pouring process. The mud is thickened and coagulated because of the cement contained in the mud, and the depth measurement is inaccurate. During the pouring process, attention should be paid to the conditions of concrete falling in the pipe and water level rising in the hole, the height of the top surface of the concrete in the hole is measured in time, and the lifting and the dismantling of the guide pipe are correctly commanded.
When the guide pipe is lifted to a certain height above the exposed hole of the tray joint, one or two sections of guide pipes are removed. At the moment, the pouring is suspended, the funnel is taken away firstly, the guide pipe at the wellhead is fastened again, the lifting equipment is hung, then the joint bolt of the guide pipe is loosened, meanwhile, the lifting hook for lifting the guide pipe is hung on the lifting ring at the upper end of the guide pipe to be dismounted, the dismounted guide pipe is hung away after the bolts are completely dismounted, the concrete funnel is connected to the guide pipe at the wellhead again, the position is corrected, and the pouring is continued.
The catheter removal was performed quickly and controlled for 10 min. Bolts, rubber pads and tools are prevented from falling into the holes and personal safety is taken care of. The removed pipe joints need to be cleaned immediately and stacked orderly.
After the underwater concrete is poured, the underwater concrete is maintained by adopting a method of digging and burying, so that the concrete meets the requirement of the designed strength, and meanwhile, the underwater concrete is prevented from being damaged after being formed into a pile for a long time. And (3) excavating the pile head when the maintenance age reaches 28 days (or the concrete strength reaches 70% of the design strength and is not less than 15MPa), chiseling the floating slurry on the top surface of the pile foundation to the design elevation, cutting off the sound measurement pipe, carrying out ultrasonic detection, wherein the bottom of the sound measurement pipe is flush with the bottom of the pile foundation, and the top of the sound measurement pipe exceeds the design elevation of the pile foundation by 50 cm.
The pile quality detection of the pile foundation adopts an ultrasonic detection method, when the pile quality is I-type pile, the pile quality is good, and the next procedure can be performed; when the pile quality is II-type pile, re-testing by adopting a core drilling and sampling method; when the acoustic pipe is blocked by the acoustic pipe, the quality of the pile is detected by core drilling sampling.
S5, performing inter-pile precipitation operation;
the construction process of the dewatering well comprises the following steps: well point measuring and positioning → well head digging, a safety and protection cylinder → a drilling machine in place → drilling hole → backfilling a sand cushion layer at the bottom of a well bottom → hanging and releasing a well pipe → backfilling a gravel filter layer between the well pipe and the wall of the hole → well washing → arranging a water pump in the well pipe, installing a water pumping control circuit → trying to pump water → normal work of a precipitation well → pulling the well pipe after precipitation is finished → well sealing.
The dewatering well is carried out 20 days before the foundation pit is excavated, so that the stagnant water in the stratum is drained in advance, the underground water level is reduced, the soil layer self-stabilizing capability is improved, and the waterless operation is smoothly carried out. When the dewatering well pumps water, the pumping interval time of the submersible pump is from short to long, the pump should be stopped immediately after each pumping in the dewatering well, and the pumping frequency of the well with large water yield per day should be increased properly.
And in the precipitation running process, the water level observation work of each well is well done, and the change condition of the confined aquifer water head is mastered in time. During the operation period of the precipitation, the on-site 24-hour duty system is implemented, and the duty personnel need to carefully make various quality records, so that the accuracy and completeness are achieved. The recording of the precipitation operation in the precipitation operation process is analyzed and sorted in time, and various necessary charts are drawn so as to reasonably guide the precipitation operation and improve the precipitation operation effect. And submitting one precipitation operation record every day, and measuring the water level of the pumping-stopped well in time for 1-2 times every day.
Note that: preparing drainage preparation work in the foundation pit, and ensuring that rainwater and other seeping water in the foundation pit can be drained in time; the working state of the pump is frequently checked in the precipitation operation stage, and the pump is changed or repaired in time once the abnormality is found; and the power supply is ensured in the precipitation operation stage, if the power grid is cut off, the standby generator is started in time, and the precipitation effect is ensured.
And S6, performing initial excavation construction on the soil body between the piles.
In the step, the earthwork excavation is carried out after the concrete of the cast-in-place pile reaches the age, the temporary access road at the sea side and the existing access road between the piles are utilized during the earthwork excavation, and the dewatering well between the piles does not intermittently drain water during the construction period, so that the underground water level is ensured to be lower than +3.0 m.
And S7, performing cast-in-place concrete pile cap construction on the top of the pile foundation.
Specifically, a scaffold is built in the step, a forming die of a pile cap is arranged at the top of a pile foundation, a reinforcement cage is built in the die, and then the pile cap is cast and formed by adopting a concrete cast-in-place process. And (5) after the structural strength is established, removing the forming die and maintaining.
S8, excavating the soil body of the wharf berthed water area; the step adopts a conventional excavation process.
S9, performing secondary excavation construction on the soil body between the piles;
in this step, the inter-pile soil is excavated to elevation +0.0 m. The excavation is firstly carried out from the sea side, a 450 type long arm excavator is used for deep excavation operation among piles, the excavator is positioned in front of the first row of cast-in-place piles, the long arm is lifted after excavation, a rear rotating area is not in contact with pile caps so as to prevent the excavator from damaging the cast-in-place pile caps when rotating, the 450 type long arm excavator (main arm 18m) can only excavate to the middle position of the third row to the fourth row of cast-in-place piles according to a cross section diagram of a wharf and the position of a berth water area, and the rest soil among the piles on the land side is excavated when the earthwork of a shore-connecting structure is excavated.
When the soil among the piles is excavated, the piles are excavated in layers, stages and steps, and the excavation depth of each layer is not more than 1.5m, so that the pile squeezing effect of the soil among the piles on the cast-in-place piles is prevented.
S10, mounting beam and plate prefabricated components above the pile caps, and mounting ship-leaning components;
after the maintenance conditions of the prefabricated parts meet the requirements and the strength meets the design, the prefabricated parts are hoisted to a beam transporting plate car through a precast yard truck, and the plate car is transported to a construction site for hoisting and installation.
According to the design section diagram and on-site plan arrangement, the original temporary sidewalk with the width of 10m in the berthed water area is planned to be used for firstly installing two rows of prefabricated components on the sea side, after a working face is provided, an east-west temporary road is built from the temporary sidewalk in the berthed water area and leads to the upper part of the installed prefabricated components, and 50t of crawler crane goes ashore for installing the prefabricated components.
Before the crawler crane goes ashore, a steel plate is laid on the surface of the installed prefabricated part, and in order to prevent the steel plate from damaging the installed prefabricated part, the steel plate is wrapped by geotextile and wound. To ensure the overall stability of the wharf in the installed area, the two track shoes of the crane must be seated above the pile foundations and above the cross beams, not allowing the two track shoes to be seated above the prefabricated panels at the same time.
S11, performing cast-in-place concrete construction on the reserved joints among the prefabricated parts to enable the prefabricated parts to be connected into a whole;
in the step, the prefabricated parts and the pile caps form an integral supporting plane by connecting the reserved joint parts of the prefabricated parts through cast-in-place concrete.
S12, casting a concrete surface layer and a wearing layer on the top surface;
the process of the step comprises the following steps: pouring concrete in slab joints → binding reinforcing steel bars in surface layers → installing embedded iron pieces → erecting side molds → pouring surface layers in blocks. Before the slab joints are constructed on the surface layer, the construction of the slab joints is firstly completed, and the slab joints are constructed in a mode of adopting an upper hanging bamboo plywood as a bottom formwork; the interval plate is poured in two times, and 10cm (including a wearing layer) is reserved during the first pouring and is used as a surface folding during the second pouring. The main beam is placed on the wharf surface layer, the secondary beam is hung downwards through the hanging rod, and the bottom die is a wood die made of bamboo plywood and square wood. And the accurate construction of the deformation joint is noticed. The supply and pouring of concrete are the same as those of the cast-in-place member, and in order to ensure the surface layer quality, the weather needs to be selected during construction, and the concrete pouring and vibrating quality needs to be controlled. After the concrete is put in a warehouse, the concrete is evenly divided and leveled manually, a flat plate vibrator is used for compacting, the top elevation of the surface layer is well determined by using side molds (small-sized channel steel or angle steel and the like) arranged among the blocks, and the leveling is performed back and forth by using a roller. The cement paste with a layer of thickness is formed, when the bleeding is serious, the vacuum water absorber is used for removing the water on the surface so as to ensure the quality of the surface layer, and finally, the leveling and the press polishing are manually matched. In the pouring process, rainproof measures must be taken so as not to influence the strength and appearance quality of the concrete.
And S13, carrying out dredging construction on the front edge area of the pile foundation wharf.
In the step, the prior dredging construction process is adopted to carry out dredging construction on the front edge area of the pile foundation wharf, such as the dredging construction of a channel and a berth by adopting equipment such as a grab dredger, a trailing suction dredger, a cutter suction dredger and the like
In step S4, the construction of the pile foundation is performed simultaneously with the construction of the pile foundation, and the pile foundation is a construction between the pile foundation and the landing zone, and generally includes a riprap foundation, a retaining wall, a riprap prism, and the like.
The construction process of the shore connection project comprises the following steps of (1) digging a precipitation well in a shore connection area, and carrying out precipitation operation; (2) carrying out earth excavation operation of the shore-connecting zone; (3) performing vibroflotation pile construction in a shore connection zone; (4) constructing a riprap foundation bed; (5) constructing a concrete stone-doped retaining wall on the riprap foundation bed; (6) constructing a riprap prism on the outer side of the concrete stone-doped retaining wall, and constructing a reversed filtering layer on the outer side of the riprap prism; (7) and backfilling a hill skin stone outside the inverted filter layer, and constructing a pavement structure layer above the inverted filter layer and the backfilled hill skin stone layer.
And (2) in the step (1), a dewatering well is dug in the shore area, so that the water level height of underground water in the shore area is reduced.
And (2) performing earthwork excavation operation of the shore connection zone, and excavating a foundation pit of the shore connection zone.
And the earth excavation of the shore connection structure is carried out after three rows of dewatering wells on the land side are finished and the water level is lower than the first excavation elevation, the earth excavation top elevation is +5.7m of the original elevation, and the excavation bottom elevation is-2.0 m. And during construction operation, the water level is lower than the excavation working surface by layering, segmenting and excavating by steps, the excavation thickness of each layer is not more than 1.5m, and meanwhile, the dewatering well does not intermittently pump water. Before formal construction, a 30m structure section is selected as a typical construction section, the construction precipitation effect and the construction work efficiency are mainly considered, and after the expected work efficiency is met, formal construction is carried out, and if the expected work efficiency is not met, adjustment is carried out additionally.
During excavation, a 200-type excavator is used to go deep into the area between piles on the sea side as far as possible, the soil between the piles is excavated, and the residual earthwork is excavated to the elevation of minus 2.0m by using a 450-type long arm excavator (main arm 18 m). The excavation of soil among piles is carried out along with the excavation depth of soil of a shore connecting structure, the shore connecting structure is lowered by one layer, the inter-pile area is lowered by one layer, for the soil of the southern and northern inter-pile area, if the soil cannot naturally collapse, the area (the pile distance is 5.3m) between the last row of piles and the penultimate row of piles enters the inter-pile area to be cleaned by adopting a 60-type excavator (the width of the outer edge of a crawler belt is 2.5m), and the rest inter-pile distances cannot meet the requirement of entering of the 60-type excavator, and manual cleaning is adopted.
The soil between the piles is excavated to +0.0m, the water area where the wharf of the pile foundation is moored is excavated to +3.0m, and the slope ratio between the soil and the water area is 1:3. Constructing from +3.0m to average tide level +1.87m (high water level +4.39m is designed, low water level +0.65m is designed, and the average tide level is the average value of the two) in a front-edge berthed water area by adopting a 200-type backhoe, and excavating to the average tide level +1.87m, and excavating the residual soil between piles (from the first row of piles to the fourth row of piles +0.0m to the designed elevation) to the designed elevation by using a 450-type long-arm excavator (with the main arm being 18m long) when the tide is lowered according to the daily tide level. And calculating the section diagram of the remaining berthed water area according to the design drawing, wherein the land excavation mode is basically infeasible, the subsequent harbor basin and the channel can be combined for dredging, the land excavation unit price is basically consistent with the dredging unit price through measurement and calculation, and the part of the earthwork plan and the front edge dredging are excavated by using a dredger.
And (3) performing vibroflotation pile construction in the shore connection zone.
The non-filler vibroflotation construction is carried out after earthwork excavation reaches minus 2.0m, after the earthwork excavation reaches the designed bottom elevation, the vibroflotation construction adopts a 50t crawler crane and a 75KW vibroflotation device, three rows of vibroflotation piles are positioned between the last two rows of filling piles according to a designed section diagram, in order to reduce the influence on the constructed pile foundation, the front three rows of vibroflotation piles use single-point resonance, and the back vibroflotation piles adopt a three-point resonance mode.
After the land connection earth side is excavated to the designed elevation, if the dewatering well drains water, the stratum meets the bearing capacity requirement of the crawler crane, and the construction can be directly carried out; if the requirement of bearing capacity is not met, in order to reduce hardened sidewalks, filling a half-width riprap foundation bed, enabling the crawler crane to sit on the riprap foundation bed to perform vibroflotation operation, filling the riprap foundation bed immediately after vibroflotation areas are finished, and then sitting on paved areas to perform vibroflotation construction of unpaved areas. The process can reduce the pavement of the sidewalk, and if the work efficiency of filling the riprap foundation bed and the vibroflotation pile is obviously reduced, the pavement of the sidewalk is required.
A, transporting block stone materials to a construction site on a road, wherein the block stones are fresh, seriously weathered, crack-free and non-flaky open mountain stones, and the weight of the block stones is 10-100 kg; B. carrying out riprap filling on the block stones to form a riprap foundation bed main body; C. filling fine materials on the riprap foundation bed main body and rolling; D. and (5) arranging the slope of the roadside slope surface of the riprap foundation bed.
The weight gradation of the block stone should be adjusted as much as possible to meet the requirement of compaction. The average contour line of the riprap section is not less than the design section, and the gradient is not steeper than the design requirement. After each section of stone is pushed and filled, the slope should be managed in time. The stone is required to be hard in texture, not flaky and free of weathering peeling and cracks, and the weight of a single block of stone is required to meet the requirements of design documents. Uniaxial saturation ultimate compressive strength of the block stone: the lump stone is not less than 30 MPa. The weight of the block stone is more than 25kN/m3. The rock block 20t dump truck is transported to the site for dumping and filling, and is leveled by a 160 model bulldozer on site. And (3) filling joints between the stones by using fine materials meeting the standard requirements, then rolling and compacting by using a vibratory roller according to the design requirements, and meanwhile, arranging the slope by using machinery. The prefabricated member can be used as a pavement for installing the land side prefabricated member after the construction requirement is met.
The construction process for constructing the concrete stone-doped retaining wall in the step (5) comprises the following steps of A, measuring and lofting; B. erecting a mould and pouring concrete, adding block stones in the process of pouring the concrete and vibrating, wherein the using amount of the block stones is less than or equal to 20% of the volume of the retaining wall; C. pouring and vibrating concrete; D. and leveling the top surface of the retaining wall and performing subsequent maintenance.
When the stone-doped concrete is poured, the distance between the stone and the template is not less than 300mm, the stone and the template are vibrated compactly, the stone is prevented from contacting the stone template as much as possible during vibration, and the stone amount is not more than 20% of the volume of the retaining wall. The strength grade of the stone is not lower than MU60, and the technical indexes such as width, thickness, strength, volume proportion of the stone and the like are strictly controlled when the C40F300 buried stone concrete foundation is poured. After the pouring is finished and the inspection is qualified, the next procedure construction can be carried out, after the base surface is qualified, sundries, mud and loose rocks on the rock foundation are removed, and the concrete is poured after the treatment.
Before the foundation rock surface is poured and the first layer of concrete is poured, a C15 concrete cushion layer and a broken stone cushion layer are poured according to the requirements of design drawings, and the construction process ensures that the concrete and the foundation rock are well combined. The stone burying rate of the stone-buried concrete is not more than the design requirement (20%). During construction, a layer of concrete is paved, a layer of block stones is placed, and then the block stones are compacted by vibration until the block stones sink into the concrete, so that the stones cannot be laid first, and then the concrete is poured. The block stone is solid, undegraded, crack-free and clean, and is cleaned with the saturated compressive strength not less than 60 MPa. When pouring, a layer of concrete with the thickness of 100-150 mm is paved for bottoming, and then stone is paved. The stones are laid and uniformly arranged, so that the big end faces downwards, the small end faces upwards, and the grains of the stones are vertical to the stress direction. The spacing between the stones is generally not less than 100mm, and the spacing between the stones and the formwork or the wall of the groove is not less than 300mm, so as to ensure that each stone is wrapped by concrete.
And after the stone is paved, continuously pouring concrete with the thickness of about 200-250 mm, and vibrating by using a vibrating rod to avoid contacting the template and the stone. Thus, the stone and the concrete are paved layer by layer until the final layer surface, and the concrete covering layer with the thickness of not less than 100mm is arranged on the top surface of the stone. The insertion plane distribution of the vibrator and the vibrating time are required to meet the standard requirement, and the full vibrating is ensured. Dividing joints when the buried stone concrete is poured, cleaning construction joints when the concrete is continuously poured, paving a layer of cement mortar with the same grade as the concrete, and then continuously pouring the concrete and paving stones.
The construction of the expansion joint is carried out after the concrete construction is finished, and when the concrete construction is carried out, the asphalt wood board is firstly installed on the joint parting position according to the designed thickness and the template. And (3) after the concrete is collected into the warehouse, spraying water for curing within 12-18 hours, keeping the surface of the concrete moist, paving a straw curtain for moisturizing, and removing the cover after curing for seven days at normal temperature.
A, transporting block stone materials to a construction site on a road, wherein the block stone adopts fresh and non-severe weathering, non-crack and non-flaky open mountain stone, and the weight of the block stone is 10-100 kg; B. the method comprises the following steps of (1) carrying out stone throwing filling to form a stone throwing prism body; C. filling fine materials on the riprap prism body and rolling; D. arranging slopes on the road side slope surface of the riprap prism; E. laying two stone cushion layers with the thickness of 500mm on the riprap prism; F. and paving a gravel inverted filter layer with the thickness of 600mm on the two stone cushion layers.
The construction method of the riprap prism is the same as that of a riprap foundation bed, two-piece stone cushion layer construction is carried out after the slope arrangement in the prism is checked and accepted, and the construction of the gravel inverted filter layer is carried out after the two-piece stone cushion layer is checked and accepted. The dump truck is used for carrying materials into a field and unloading the materials to a place appointed by a site constructor, and the constructor instructs the excavator to throw and fill and manage the slope.
In the embodiment, the method further comprises the step of excavating the soil body between the piles into the slope by hydraulic power, wherein hydraulic equipment is adopted to excavate the soil body between the piles, the soil body in the middle is moved to the side part, the slope forming ratio is 1:3.5, and the elevation of the slope bottom is-2.0 m. The step is the final step before the project is finished, and is equivalent to the final finishing of the wharf area of the pile foundation.